Hacking Java class: Calling private Constructor of Java class outside the class

sarikazdubey

16 years ago

Here is a sample code by which you can hack and call the private constructor of a class using reflection.

public class HackMeIfYouCan {
   private HackMeIfYouCan(){
       System.out.println(“I m hacked”);
    }
}

public class Test {

public static void main(String[] args) throws Exception {

Constructor c[] = HackMeIfYouCan.class.getDeclaredConstructors();

c[0].setAccessible(true);

c[0].newInstance(null);

}

}

Here is the output of this program

I m hacked

So if you want your java class to be protected make sure you dont give ReflectPermission to your class.